This invention relates to a substrate processing apparatus belonging to a semiconductor producing apparatus for processing a substrate successively and continuously with various different processings.
A substrate processing apparatus of this kind hitherto used does not include a separation chamber or "idle chamber" which is an essential feature of the present invention as later described.
Referring to FIG. 1, the apparatus of the prior art includes a load lock chamber 6 and a buffer chamber 5 for loading and unloading a substrate between the atmosphere and the processing apparatus, and a substrate processing chamber 4, these chambers being directly connected. (The load lock and buffer chambers 6 and 5 are referred to hereinafter as "input and output chambers".) For example, for the purpose of depositing three film layers on a substrate, cathodes 41, 42 and 43 are arranged in the substrate processing chamber 4. The substrate is transferred as shown by an arrow 44 so as to face the respective cathodes successively so that each separate sputtering process is applied to a surface of the substrate in a position facing each cathode.
In another case of the prior art, as shown in FIG. 2 an apparatus includes a load lock chamber 6 and a buffer chamber 5 next thereto for loading a substrate thereinto from the atmosphere, sputtering chambers 45, 46 and 47 for successively depositing three film layers of different materials on a surface of the substrate and a buffer chamber 5' and a load lock chamber 6' for unloading the substrate out of the apparatus into the atmosphere, these chambers being connected in series for the surface processing of the substrate.
With the apparatuses of the prior art above described, when different processings are continuously effected, these different processings sometimes interfere with each other and there are limitations of selection in kinds, orders, repetitions and the ilke of processings. Moreover, it is quite impossible to form continuous films of different material by different means, for example, the sputtering and chemical vapor depositing. In order to carry out such processing, an apparatus for this purpose becomes unavoidably bulky or is obliged to have more substrate processing chambers.
For example, if it is intended to effect a continuous etching process of a substrate by pretreatment, etching and post-treatment of the substrate, it cannot be carried out by an apparatus as shown in FIG. 1. Instead, an apparatus as shown in FIG. 2 is required. The reason why the apparatus shown in FIG. 1 cannot be employed is that the processings at the cathodes 41, 42 and 43 interfere with each other to lower the quality of the processings; and in order to obtain high quality of the processings, the apparatus is obliged to be operated with lower efficiency.
On the other hand, the apparatus as shown in FIG. 2 involves the following problems. The apparatus operates only with lower efficiency, because the processings are effected in series or one by one. Moreover, every time the gate valves are opened and closed, for example, noxious gases in the etching chambers may enter the pretreatment and post-treatment chambers to spoil the quality of the processing of a substrate.